Ocular tolerance in rabbits of intracameral administration of MYDRANE, a fixed combination of tropicamide, phenylephrine, and lidocaine for cataract surgery

Purpose Preclinical studies have been done to evaluate the ocular tolerance of MYDRANE (tropicamide 0.02%, phenylephrine 0.31% and lidocaïne 1%) after a single intracameral (IC) injection in rabbits. Methods 60 pigmented rabbits were divided in 3 groups of 10 animals by injection volume (100 or 200 μl of MYDRANE or 0.9% NaCl). One group injected with MYDRANE and the group injected with NaCl had their anterior chamber rinsed with NaCl, 1 min after IC injection. This wash was not performed for the second MYDRANE‐group in order to extend the presence of the product in the anterior chamber well beyond what is expected in clinical use. Animals were held in observation for 7 days. The following evaluations were performed: general tolerance, slit‐lamp observations, laser flare, cornea thickness, cell density of the corneal endothelium, electroretinography. After euthanasia, eyes were sampled for histology. Results MYDRANE was very well tolerated with or without rinsing. Very slight conjunctival effects were observed for 3 or 4 animals from groups after 200 μl‐injection and very slight corneal vascularization was observed for one animal from NaCl‐group. Inflammation in the anterior chamber was mainly observed in the eyes who were rinsed and this inflammation decreased in the course of time. Iris, fundus and lens were normal, except for 4 animals in whom a needle impact was observed on the lens, probably due to rinsing. In addition, whatever the group, cornea thickness, endothelium cell density, electroretinography parameters and ocular histology were not affected. Conclusions Following IC injection of 100 or 200 μl of MYDRANE, which is the maximal injectable volume in rabbits, the ocular tolerance of MYDRANE was very good for 7 days and the ocular effects observed were attributed mainly to the method of injection and to the rinsing.